Save Joaquin!! Or not...

Joaquin Phoenix appeared on David Letterman last night. Did you see it? Have you seen the clip? There are five possible explanations for this humorous/sad/painful interview:

a) Joaquin has gone completely batshit;
b) Joaquin is painfully shy and was forced to be on the show by his publicist;
c) Joaquin is on something bad;
d) Joaquin became possessed by the ghost of Johnny Cash during the filming of Walk the Line, thus opening a portal for other dead celebrities to enter his body, including Anna Nicole Smith and perhaps Kurt Cobain;
e) Joaquin is embracing his bad press and exploiting it.

I tend to believe the explanation is e, because the guy is just too brilliant for it to be anything else. What do you think?